The background description provided herein is for the purpose of generally presenting the context of the present invention. The subject matter discussed in the background of the invention section should not be assumed to be prior art merely as a result of its mention in the background of the invention section. Similarly, a problem mentioned in the background of the invention section or associated with the subject matter of the background of the invention section should not be assumed to have been previously recognized in the prior art.
When a power grid has a large scale blackout accident or the power grid collapses, if the power grid is restored too slowly or collapses again, the blackout time of users is prolonged and the social impact is expanded, thereby bringing great loss to national economy and people's daily life, and even affecting social stability. Therefore, researches related to power grid black-start have drawn greatly attention domestically and abroad. Current researches on power grid black-start mainly focus on three aspects including a black-start research scheme, a black-start test scheme, and a black-start dispatching operation scheme. The black-start research scheme attacts more attention than the other two, which includes subsystem partitions, black-start power source and black-start path selections, self-excitation, overvoltage calculations, and optimized selections of different black-start research schemes based on certain optimization algorithms. In addition, researches also include relay protections and automatic safety devices during the black-start in a secondary system.
In the current power grid black-start research scheme, subsystems are divided, firstly, then related electrical calculations are conducted from the black-start power source along the black-start paths, so as to start another power source and a transformer, and restore corresponding load, thereby gradually restoring operation of the subsystem. Each subsystem can conduct black-start by using an internal black-start power source or an external black-start power source. Parallelization between the started subsystems is not focused by the current black-start research scheme. Therefore, the power grid black-start research scheme is actually a black-start research scheme of each subsystem of the power grid.
The present invention provides a parallelization method that is different from the above researches. The parallelization method is neither a black-start research scheme of a certain subsystem, nor a black-start test scheme or dispatching operation scheme. Instead, the parallelization method for the black-start subsystems of a power grid implements parallelization of the subsystems at certain determined voltage levels. The parallelization method for the black-start subsystems when the power grid has an external black-start power source support is greatly different from that when the power grid does not have an external black-start power source support. The present invention provides a parallelization method for black-start subsystems of a power grid with external support.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.